To improve the bandwidth of NAND flash memory without adding major costs to the device, or to get higher density in a NAND flash memory system, multiple memory devices may be associated together in various sizes of groupings. Several memory devices may be grouped into a set, while multiple sets may be grouped into a memory module. Sometimes the same operation (e.g., go into sleep mode.) is to be performed by all the devices in a group. However, conventional systems must select and instruct each device separately, even if many devices are supposed to perform the same operation at the same time. This adds to the overhead of operating the memory system.